<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width= , initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <h2>当前计数：{{counter}}</h2>
        <!-- <button v-on:click="counter++">+</button>
        <button v-on:click="counter--">-</button> -->
        <button v-on:click="add">+</button>
        <button @click="sub">-</button>   
        <!-- 语法糖： v-on的简写 -->
    </div>
    <script src="../js/vue.js"></script>
    <script>
        // proxy == 代理
        const obj = {
            counter: 0
        }
         const app = new Vue({
            el: '#app',    
            // data: {    
            //     counter: 0  
            // },
            data: obj,
            methods: {
                add: function () {
                    console.log("add被执行");
                    this.counter++;
                },
                sub: function () {
                    console.log("sub被执行");
                    this.counter--;
                }
            }
        })
    </script>
</body>
</html>